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SubjectRe: [BUG] ssb: Possible sleep-in-atomic bugs in ssb_pcmcia_read8
On Mon, 9 Oct 2017 09:29:17 +0800
Jia-Ju Bai <baijiaju1990@163.com> wrote:

> According to pcmcia.c, the driver may sleep under a spinlock.
> The function call paths are:
> ssb_pcmcia_read8 (acquire the spinlock)
> select_core_and_segment
> ssb_pcmcia_switch_segment
> ssb_pcmcia_cfg_write
> pcmcia_write_config_byte
> pcmcia_access_config (drivers/pcmcia/pcmcia_resource.c)
> mutex_lock --> may sleep
>
> ssb_pcmcia_read8 (acquire the spinlock)
> select_core_and_segment
> ssb_pcmcia_switch_segment
> sssb_pcmcia_cfg_read
> pcmcia_read_config_byte
> pcmcia_access_config (drivers/pcmcia/pcmcia_resource.c)
> mutex_lock --> may sleep
>
> A possible fix is to use spinlock instead of mutex lock in
> pcmcia_access_config in drivers/pcmcia/pcmcia_resource.c.
>
> These bugs are found by my static analysis tool and my code review.



Thanks for scanning and your resulting bug notification.
I currently don't have the hardware at hand to develop and test a
proper fix for this.
That said, I'm not so sure anymore why bar_lock is a spinlock instead
of a mutex. It might be possible to convert this to mutex.

I will try to look into this.

--
Michael
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